Pharmaceutical Management of Trigeminal Neuralgia in the Elderly

Effects of carbamazepine on BDNF expression in trigeminal ganglia and serum in rats with trigeminal neuralgia

OBJECTIVES

Trigeminal neuralgia (TN) is a severe chronic neuropathic pain that mainly affects the distribution area of the trigeminal nerve with limited treating efficacy. There are numerous treatments for TN, but currently the main clinical approach is to suppress pain by carbamazepine (CBZ). Brain-derived neurotrophic factor (BDNF) is closely related to chronic pain. This study aims to determine the effects of CBZ treatment on BDNF expression in both the trigeminal ganglion (TG) and serum of TN via a chronic constriction injury of the infraorbital nerve (ION-CCI) rat model.

METHODS

The ION-CCI models were established in male Sprague-Dawley rats and were randomly divided into a sham group, a TN group, a TN+low-dose CBZ treatment group (TN+20 mg/kg CBZ group), a TN+medium-dose CBZ treatment group (TN+40 mg/kg CBZ group), and a TN+high-dose CBZ treatment group (TN+80 mg/kg CBZ group). The mechanical pain threshold in each group of rats was measured regularly before and after surgery. The expressions of BDNF and tyrosine kinase receptor B (TrkB) mRNA in TGs of rats in different groups were determined by real-time PCR, and the expression of BDNF protein on neurons in TGs was observed by immunofluorescence. Western Blotting was used to detect the protein expression of BDNF, TrkB, extracellular regulated protein kinases (ERK), and phospho-extracellular regulated protein kinases (p-ERK) in TGs of rats in different groups. The expression of BDNF in the serum of rats in different groups was detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The results of mechanical pain sensitivity showed that there was no significant difference in the mechanical pain threshold in the right facial sensory area of the experimental rats in each group before surgery (all P>0.05). From the 3rd day after operation, the mechanical pain threshold of rats in the TN group was significantly lower than that in the sham group (all P<0.01), and the mechanical pain threshold of rats in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 CBZ mg/kg group was higher than that in the TN group (all P<0.05). The BDNF and TrkB mRNA and protein expressions in TGs of rats in the TN group were higher than those in the sham group (all P<0.05), and those in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than the TN group (all P<0.05). The p-ERK levels in TG of rats in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were significantly decreased compared with the TN group (all P<0.05). The BDNF and neuron-specific nuclear protein (NeuN) were mainly co-expressed in neuron of TGs in the TN group and they were significantly higher than those in the sham group (all P<0.05). The co-labeled expressions of BDNF and NeuN in TGs of the TN+ 80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than those in the TN group (all P<0.05). The results of ELISA showed that the level of BDNF in the serum of the TN group was significantly higher than that in the sham group (P<0.05). The levels of BDNF in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than those in the TN group (all P<0.05). Spearman correlation analysis showed that the BDNF level in serum was negatively correlated with mechanical pain threshold (r=-0.650, P<0.01).

CONCLUSIONS

CBZ treatment can inhibit the expression of BDNF and TrkB in the TGs of TN rats, reduce the level of BDNF in serum of TN rats and the phosphorylation of ERK signaling pathway, so as to inhibit TN. The serum level of BDNF can be considered as an indicator for the diagnosis and prognosis of TN.

Therapeutic Approach for Trigeminal Neuralgia: A Systematic Review

This umbrella review aimed to determine the various drugs used to treat trigeminal neuralgia (TN) and to evaluate their efficacies as well as side effects by surveying previously published reviews. An online search was conducted using PubMed, CRD, EBSCO, Web of Science, Scopus, and the Cochrane Library with no limits on publication date or patients' gender, age, and ethnicity. Reviews and meta-analyses of randomized controlled trials pertaining to drug therapy for TN, and other relevant review articles added from their reference lists, were evaluated. Rapid reviews, reviews published in languages other than English, and reviews of laboratory studies, case reports, and series were excluded. A total of 588 articles were initially collected; 127 full-text articles were evaluated after removing the duplicates and screening the titles and abstracts, and 11 articles were finally included in this study. Except for carbamazepine, most of the drugs had been inadequately studied. Carbamazepine and oxcarbazepine continue to be the first choice for medication for classical TN. Lamotrigine and baclofen can be regarded as second-line drugs to treat patients not responding to first-line medication or for patients having intolerable side effects from carbamazepine. Drug combinations using carbamazepine, baclofen, gabapentin, ropivacaine, tizanidine, and pimozide can yield satisfactory results and improve the tolerance to the treatment. Intravenous lidocaine can be used to treat acute exaggerations and botulinum toxin-A can be used in refractory cases. Proparacaine, dextromethorphan, and tocainide were reported to be inappropriate for treating TN. Anticonvulsants are successful in managing trigeminal neuralgia; nevertheless, there have been few studies with high levels of proof, making it challenging to compare or even combine their results in a statistically useful way. New research on other drugs, combination therapies, and newer formulations, such as vixotrigine, is awaited. There is conclusive evidence for the efficacy of pharmacological drugs in the treatment of TN.

Xper-CT combined with laser-assisted navigation radiofrequency thermocoagulation in the treatment of trigeminal neuralgia

Objective

Our objective was to study the clinical feasibility of Xper-CT combined with laser-assisted radiofrequency thermocoagulation in the treatment of trigeminal neuralgia.

Materials and methods

A retrospective analysis was made of 60 patients with trigeminal neuralgia who visited the Affiliated Hospital of Binzhou Medical University from January 2019 to May 2021. According to the different surgical methods, we were divided into C-arm X-ray group and laser navigation group. The operation time, operative complications, post-operative 24 h, post-operative 3 and 6 months Barrow Neurotics Institute (BNI) score were recorded and compared.

Results

Compared with the C-arm X-ray-guided puncture group, Xper-CT combined with laser-assisted navigation has the obvious advantages of shorter total puncture time, shorter surgical time, higher success rate of first puncture, and better surgical effect.

Conclusion

Radiofrequency therapy of trigeminal neuralgia with Xper-CT combined with laser-assisted navigation has a good clinical effect and can be promoted and applied.

Efficacy and complications of microvascular decompression in patients over 70 years with trigeminal neuralgia

OBJECTIVE

Treatment of choice for trigeminal neuralgia (TN) by neurovascular conflict in case of failure of medical treatment is microvascular decompression (MVD). It is a safe and effective technique in the short and long term. But what about older patients who are considered more fragile anesthetically and surgically? Our Objective is to demonstrate the efficacy and complication rate of microvascular decompression (MVD) for older and younger patients with trigeminal neuralgia (TN) due to neurovascular conflict.

METHODS

102 patients with TN due to neurovascular conflict were included (June 2005-December 2016) in a single Regional hospital. 25 were included in the group composed of ≥ 70-year-old patients (G1), while 77 were included in the < 70-year-old group (G2). The patients were operated on by the same surgical team using a retro-sigmoid approach to access the neurovascular conflict. The epidemiologic, clinical, anesthetic, and surgical data were extracted.

RESULTS

The immediate efficacy of surgical treatment (BNI pain intensity = I) was 96% in G1 and 96.10% in the G2 group (p = 0.71). At 3-year follow-up, the efficacy rate was 89% and 86%, respectively (p = 0.93). At 5 years, it was 92% and 92% (p = 0.98). Complication rates were comparable between the two groups (20% versus 27%; p = 0.47) and no deaths occurred despite the fact that G1 group had worst preoperative anesthetic score (ASA-NYHA).

CONCLUSION

MVD is a durable procedure in patients over 70 years of age diagnosed with essential TN. The complication rate and immediate-, medium-, and long-term efficacy were similar to those of younger patients.

Microvascular decompression for pediatric onset trigeminal neuralgia: patterns and variation

OBJECTIVES

Pediatric trigeminal neuralgia has been rarely reported in the literature, which were only 28 cases. Although microvascular decompression (MVD) has been widely accepted as effective therapy for trigeminal neuralgia, the etiology and surgical treatment of pediatric ones are seldom addressed. We report our experience with MVD for pediatric trigeminal neuralgia patients with emphasis on the vascular conflict patterns and surgical skills.

METHODS

This retrospective report included 11 pediatric TN patients, who underwent MVD and were followed for 3-86 months. The data were retrospectively analyzed with emphasis on the clinical features.

RESULTS

This series included 4 boys and 7 girls with average age of 13 ± 3.4 years old, their onset age were from 7 to 18 years old. The singular vein and combined artery/vein conflictions account for 7/11. 9 (81.8%) patients achieved immediate excellent outcomes. One recurrence was observed after 5 months and refused the second surgery.

CONCLUSIONS

The etiology of pediatric onset trigeminal neuralgia is still vascular conflict, whose patterns are different from adults, of which combined artery/vein and singular venous compression patterns have a much more higher proportion. Because of the smaller operative space and fragile-thin venous wall with adhesion to other structures, it is much more difficult to decompress the trigeminal nerve among pediatric patients. Sufficient arachnoid release, full exploration, and decompression along the trigeminal nerve were necessary, which will increase the excellent rate among pediatric patients.

Efficacy of medications in adult patients with trigeminal neuralgia compared to placebo intervention: a systematic review with meta-analyses

Background

Trigeminal neuralgia (TN) is characterized by brief, unilateral, sharp, stabbing, and shooting pain of the fifth cranial nerve. The objective of this systematic review with meta-analysis was to determine the effect of medications compared to placebo in adult patients with TN.

Methods

Review authors identified randomized placebo-controlled trials (RCTs) from PubMed, Web of Science, Cochrane, and EMBASE up to February 2021. We assessed the inclusion and exclusion criteria as well as the risk of bias of the studies based on the Cochrane Handbook. A total of 324 unduplicated references were scanned independently and reduced to eight relevant RCTs, with 89 patients included. Medications investigated included oral carbamazepine, subcutaneous sumatriptan, lidocaine (intranasal, 8% spray on the oral mucosa or intravenous), buprenorphine (ganglionic local opioid analgesia), and oral Nav1.7, a selective sodium channel blocker.

Results

Meta-analyses showed that overall patients receiving lidocaine reported a significantly lower post-treatment intensity of pain -3.8 points on a 0-10 scale (95% Cl = -4.653 to -2.873; P < 0.001). Patients who received lidocaine were 8.62 times more likely to have pain improvement than patients on placebo (P < 0.001). In one RCT, patients receiving oral carbamazepine showed a significant improvement in pain intensity of -32% compared to the placebo (P < 0.001). In one trial, patients receiving 3 mg subcutaneous sumatriptan had a significantly lower intensity of pain on average -6.1 points on a scale of 0-10 compared to placebo (P < 0.001) and a significant improvement in pain intensity of -75% compared to the improvement in the placebo group (P < 0.001). Patients who received subcutaneous sumatriptan were 10 times more likely to have pain improvement than those who received placebo (P = 0.001) in one study. Due to the unclear/high risk of bias and small sample size, the quality of the evidence for lidocaine in the treatment of TN was low.

Conclusion

Further studies are needed for carbamazepine, sumatriptan, buprenorphine, and oral Nav1.7 sodium channel blockers, as only one study reported outcomes.

Medical Management of Trigeminal Neuralgia

Background

Trigeminal neuralgia (TN) is a painful condition, often leading to poor quality of life.

Objective

The aim of this review was to discuss the various treatment modalities for the medical management of TN.

Materials and Methods

We reviewed the available literature on TN in clinical databases including PubMed, Google Scholar, and the Cochrane Database of Systematic Reviews, with a specific focus on the pharmacological treatment and newer drugs under development for the treatment of TN.

Results

Carbamazepine (CBZ) is the gold standard of treatment for TN. The first-line drugs for the treatment of TN are CBZ and oxcarbazepine (OXC). A proportion of cases (30%) are initially resistant to the first-line drugs. Alternative drugs need to be considered if the first-line drugs are not well tolerated or become ineffective with prolonged therapy. The second-line drugs comprise lamotrigine, baclofen, gabapentin, and pregabalin used as monotherapy or in combination with CBZ/OXC. Botulinum toxin A may be a promising presurgical option. Newer drug like vixotrigine has shown good results in phase two randomized control trials. About 50% of cases develop treatment resistance to oral drugs over the subsequent years of therapy and require surgical options.

Conclusion

The first-line drugs for the treatment of TN (irrespective of the age group or type) are CBZ and OXC. Combination therapy with second-line or other drugs may become necessary with poor response to CBZ/OXC, or if adverse events occur. Patients should be offered surgical options if there is poor response or tolerance to the medical therapy.

An Effective Phytoconstituent Aconitine: A Realistic Approach for the Treatment of Trigeminal Neuralgia

Trigeminal neuralgia pain remains a challenge to treat. Natural compounds may be promising options for relieving pain. This study was aimed at investigating the effects of aconitine in a rat model of trigeminal neuralgia pain. Infraorbital nerve chronic constriction injury was performed in adult Wistar Albino rats. After the neuropathic pain developed, the rats were assigned to one of the treatment groups: carbamazepine 40 or 80 mg/kg; aconitine 0.25, 0.50, or 0.75 mg/kg; or saline injection (control group). Behavioral testing with von Frey filaments and the rotarod test were carried out before the surgical procedure and on the 24th to 29th postoperative days. Following the completion of tests, ipsilateral and contralateral spinal cords were harvested for Western blot analyses to assess NR-1 protein expression. ANOVA followed by Mann-Whitney U test was performed for the statistical analyses. P values of <0.05 were considered significant. Aconitine significantly reduced mechanical sensitivity in a dose-dependent manner. A significant reduction in motor coordination was noted for the higher doses of aconitine which was similar with the 40 and 80 mg/kg doses of carbamazepine. NR-1 expression was reduced in the ipsilateral spinal cord, whereas no significant difference was noted between the groups in the expression of NR-1 in the contralateral spinal cord. Aconitine had a significant pain relieving effect, which was similar to carbamazepine, in a dose-dependent manner. Aconitine may be an alternative pharmacological agent for the control of trigeminal neuralgia pain.

Microvascular decompression for trigeminal neuralgia in the elderly: efficacy and safety

OBJECTIVE

The safety and efficacy of surgical microvascular decompression (MVD) in elderly patients with trigeminal neuralgia (TN) is controversially discussed in the literature. A widespread reluctance to expose this cohort to major intracranial surgery persists. Our aim was to compare the efficacy and safety between older and younger patients with TN.

METHODS

In this cross-sectional study, 139 MVD procedures (103 patients < 70 and 36 patients ≥ 70) were included. Surgical fitness was assessed by the American Society of Anesthesiology (ASA) grade. The pain-free interval was evaluated using Kaplan-Meier analysis only in patients with a recent follow-up visit. Independent risk factors for recurrence in patients with a minimum 12-month follow-up were determined.

RESULTS

Patients ≥ 70 showed a significantly higher number of comorbidities. Pain intensity, affection of trigeminal branches and symptom duration was similar between groups. No significant difference in treatment associated complications and permanent neurological deficits was shown. There was no treatment-related mortality. A tendency towards a lower recurrence rate in patients < 70 did not reach statistical significance (17.6% vs. 28.6%, P = 0.274). Pain-free interval was not different between both cohorts (78.7 vs. 73.5 months, P = 0.391).

CONCLUSION

Despite a higher prevalence of comorbidities in elderly patients, complication rates and neurological deficits after MVD were comparable to younger patients. Rates of immediate and long-term pain relief compared favorably to previous studies and were similar between elderly and younger patients. These data endorse MVD as a safe and effective first-line surgical procedure for elderly patients with TN and neurovascular conflict on MRI.

Invasive and Non-Invasive Electrical Neuromodulation in Trigeminal Nerve Neuralgia: A Systematic Review and Meta-Analysis

BACKGROUND

Trigeminal neuralgia is a chronic disease characterized by intense facial pain that is caused by trigeminal nerve affectation. It usually affects adults from 50 years of age, and is more frequent in women. Additionally, it presents serious psychological effects that often lead to depression, which is why it is considered highly disabling. The therapeutic approach is based on the modification of nerve activity through electrical, surgical or chemical stimulation in specific regions of the nervous system.

OBJECTIVE

To perform a meta-analysis of the scientific literature related to invasive and non-invasive electrical neuromodulation of trigeminal neuralgia, in order to assess their effects over pain and adverse effects.

METHODS

A literature search was conducted in 4 databases, followed by a manual search of articles on invasive or non-invasive electrical neuromodulation to control the pain of trigeminal neuralgia, including the last 15 years.

RESULTS

Regarding non-invasive methods, clinical trials did not present enough results in order to perform a meta-analysis. Regarding invasive methods, clinical trials meta-analysis showed no statistical differences between different treatment methods. In all cases, improvements in patients' pain were reported, although results regarding adverse effects were variable.

CONCLUSION

In the treatment of trigeminal neuralgia, the continuous radiofrequency provides better short and medium-term results, but pulsed radiofrequency shows less adverse effects after treatment, and has better results in the long-term.

Clinical Outcome of Percutaneous Trigeminal Nerve Block in Elderly Patients in Outpatient Clinics

Objective

Trigeminal neuralgia (TN) is a severe neuropathic condition that affects several elderly patients. It is characterized by uncontrolled pain that significantly impacts the quality of life of patients. Therefore, the condition should be treated as an emergency. In the majority of patients, pain can be controlled with medication; however, other treatment modalities are being explored in those who become refractory to drug treatment. The use of the trigeminal nerve block with a local anesthetic serves as an excellent adjunct to drug treatment. This technique rapidly relieves the patient of pain while medications are being titrated to effective levels. We report the efficacy and safety of percutaneous trigeminal nerve block in elderly patients with TN at our outpatient clinic.

Methods

Twenty-one patients older than 65 years with TN received percutaneous nerve block at our outpatient clinic. We used bupivacaine (1 mL/injection site) to block the supraorbital, infraorbital, superior alveolar, mental, and inferior alveolar nerves according to pain sites of patients.

Results

All patients reported relief from pain, which decreased by approximately 78% after 2 weeks of nerve block. The effect lasted for more than 4 weeks in 12 patients and for 6 weeks in two patients. There were no complications.

Conclusion

Percutaneous nerve block procedure performed at our outpatient clinic provided immediate relief from pain to elderly patients with TN. The procedure is simple, has no serious side effects, and is easy to apply.

Acupuncture in the management of trigeminal neuralgia

BACKGROUND

We aimed to assess the standing of acupuncture as a clinical tool in the management of trigeminal neuralgia against the current first-line drug treatment (carbamazepine) and the most effective surgery (microvascular decompression (MVD)).

METHODS

Data regarding efficacy, side effects and cost were compiled for each of these three modalities from the PubMed and Cochrane Library databases. Patient stress was estimated according to Holmes and Rahe's Social Readjustment Rating Scale (SRRS).

RESULTS

Acupuncture was not significantly more effective than its corresponding control (p = 0.088), but had the greatest efficacy (mean ± 95% confidence interval) of the modalities considered (86.5% ± 5.6% compared to surgery (79.3% ± 7.7%) and pharmacotherapy (71.7% ± 2.5%), respectively). Acupuncture also had fewer mean reported side effects (22.7% ± 5.9%) compared with surgery (25.3% ± 12.6%) and pharmacotherapy (88.8% ± 25.0%), and the lowest cost; after 5 years, the cost of acupuncture was estimated to be £750, compared to £1507.73 for carbamazepine and £4878.42 for MVD. Acupuncture was the least stressful according to the SRRS (53 points), whereas surgery was second most stressful (153 points) and pharmacotherapy was the most stressful intervention to patients (217 points).

CONCLUSION

Acupuncture appears more effective than pharmacotherapy or surgery. Statistical analysis of side effects was not possible due to inconsistent reporting protocols, but the data suggest that acupuncture is considerably safer than pharmacotherapy or surgery. Acupuncture also appears to be the least expensive therapeutic modality to deliver long-term (65 weeks onwards), and our analysis indicated that it was less stressful to patients than pharmacotherapy or surgery. Further study into these areas and the practicality of its availability in the UK National Health Service (NHS) and other health systems is recommended.

Oxcarbazepine for trigeminal neuralgia may induce lower extremity weakness: A case report

BACKGROUND

Although few studies have reported hyponatremia due to carbamazepine or oxcarbazepine in patients with epilepsy, no study has investigated cases of carbamazepine- or oxcarbazepine-induced hyponatremia or unsteady gait in patients with neuropathic pain. Herein, we report a case of oxcarbazepine-induced lower leg weakness in a patient with trigeminal neuralgia and summarize the diagnosis, treatment, and changes of clinical symptoms.

CASE SUMMARY

A 78-year-old male with a history of lumbar spinal stenosis was admitted to the hospital after he experienced lancinating pain around his right cheek, eyes, and lip, and was diagnosed with trigeminal neuralgia at the right maxillary and mandibular branch. He was prescribed oxcarbazepine (600 mg/d), milnacipran (25 mg/d), and oxycodone/naloxone (20 mg/10 mg/d) for four years. Four years later, the patient experienced symptoms associated with spinal stenosis, including pain in the lower extremities and unsteady gait. His serum sodium level was 127 mmol/L. Assuming oxcarbazepine to be the cause of the hyponatremia, oxcarbazepine administration was put on hold and the patient was switched to topiramate. At subsequent visit, the patient’s serum sodium level had normalized to 143 mmol/L and his unsteady gait had improved.

CONCLUSION

Oxcarbazepine-induced hyponatremia may cause lower extremity weakness and unsteady gait, which should be differentiated from those caused by spinal stenosis.

Headache in the elderly

Headache is the most common neurologic symptom and affects nearly half the world's population at any given time. Although the prevalence declines with age, headache remains a common neurologic complaint among elderly populations. Headaches can be divided into primary and secondary causes. Primary headaches comprise about two-thirds of headaches among the elderly. They are defined by clinical criteria and are diagnosed based on symptom pattern and exclusion of secondary causes. Primary headaches include migraine, tension-type, trigeminal autonomic cephalalgias, and hypnic headache. Secondary headaches are defined by their suspected etiology. A higher index of suspicion for a secondary headache disorder is warranted in older patients with new-onset headache. They are roughly 12 times more likely to have serious underlying causes and, frequently, have different symptomatic presentations compared to younger adults. Various imaging and laboratory evaluations are indicated in the presence of any "red flag" signs or symptoms. Head CT is the procedure of choice for acute headache presentations, and brain MRI for those with chronic headache complaints. Management of headache in elderly populations can be challenging due to the presence of multiple medical comorbidities, polypharmacy, and differences in drug metabolism and clearance.

Factors Predicting Successful Outcomes for Percutaneous Radiofrequency Thermocoagulation in Patients With Idiopathic Trigeminal Neuralgia: Implications for Surgical Decision Making

OBJECTIVES

In this study we aimed to identify specific factors predicting successful outcomes after percutaneous radiofrequency thermocoagulation (RFT) for idiopathic trigeminal neuralgia (ITN) and risk factors that were associated with inferior outcomes.

METHODS

We retrospectively reviewed our cohort of 1,624 patients who underwent RFT for trigeminal neuralgia between January 2000 and December 2017. Demographic and clinical data including age, gender, disease duration, affected side, baseline pain score, pain distribution, history of previous surgical intervention, and pain characteristics were collected and evaluated for their association with outcome using univariate and multivariate logistic regression analysis.

RESULTS

78.1% of patients experienced a successful outcome of RFT for ITN as predefined criteria. Pain characteristics and history of surgical treatment were significant predictors associated with successful outcomes in regression analysis. Multivariate analysis identified provoked episodic pain at diagnosis (odds ratio [OR] = 23.629, 95% confidence interval [CI]: 16.316 to 34.219, P = 0.010), mixed pain (OR = 8.394, 95% CI: 5.951 to 11.840, P = 0.011), and no history of surgical treatment (OR = 2.189, 95% CI: 1.411 to 3.396, P = 0.019) as independent predictors for successful RFT outcome.

CONCLUSION

Presence of provoked episodic pain and mixed pain were significantly associated with successful outcome of RFT for ITN. Moreover, patients with ITN who underwent RFT for the first time were more likely to benefit from successful outcome. These findings should be considered when managing ITN with RFT to improve the likelihood of a successful outcome.

Evaluation of biochemical variables in patients with trigeminal neuralgia

The aim of this study was to evaluate the calcium, sodium, potassium, serum iron, vitamin B12, and albumin concentrations, and alkaline phosphatase (ALP) activity, in samples of serum from patients with primary trigeminal neuralgia (TN), and investigate the associations between them. Results from 73 patients who had been diagnosed with primary TN between December 2015 and 2017 were compared with those of 70 healthy subjects. Calcium (p=0.013), iron (p=0.004), and albumin (p=0.001) concentrations in the primary TN group were significantly lower than those in the control group, whereas the ALP activity was significantly higher in the TN group than in the control group (p=0.007). However, there was no significant difference in the sodium, potassium, or vitamin B12 concentrations. Biochemical variables have a role in the pathogenesis and treatment of primary TN, but there are few studies that characterise the relations between the condition and the biochemical changes. Further studies are therefore necessary to gain more information.

Postherpetic Neuralgia and Trigeminal Neuralgia

Postherpetic neuralgia (PHN) is an unpredictable complication of varicella zoster virus- (VZV-) induced herpes zoster (HZ) which often occurs in elderly and immunocompromised persons and which can induce psychosocial dysfunction and can negatively impact on quality of life. Preventive options for PHN include vaccination of high-risk persons against HZ, early use of antiviral agents, and robust management of pain during the early stage of acute herpes zoster. If it does occur, PHN may persist for months or even years after resolution of the HZ mucocutaneous eruptions, and treatment is often only partially effective. Classical trigeminal neuralgia is a severe orofacial neuropathic pain condition characterized by unilateral, brief but recurrent, lancinating paroxysmal pain confined to the distribution of one or more of the branches of the trigeminal nerve. It may be idiopathic or causally associated with vascular compression of the trigeminal nerve root. The anticonvulsive agents, carbamazepine or oxcarbazepine, constitute the first-line treatment. Microvascular decompression or ablative procedures should be considered when pharmacotherapy is ineffective or intolerable. The aim of this short review is briefly to discuss the etiopathogenesis, clinical features, and treatment of PHN and classical trigeminal neuralgia.

Research progress of mechanisms and drug therapy for neuropathic pain

Neuropathic pain is maladaptive pain caused by injury or dysfunction in peripheral and central nervous system, and remains a worldwide thorny problem leading to decreases in physical and mental quality of people's life. Currently, drug therapy is the main treatment regimen for resolving pain, while effective drugs are still unmet in medical need, and commonly used drugs such as anticonvulsants and antidepressants often make patients experience adverse drug reactions like dizziness, somnolence, severe headache, and high blood pressure. Thus, in this review we overview the anatomical physiology, underlying mechanisms of neuropathic pain to provide a better understanding in the initiation, development, maintenance, and modulation of this pervasive disease, and inspire research in the unclear mechanisms as well as potential targets. Furthermore, we summarized the existing drug therapies and new compounds that have shown antalgic effects in laboratory studies to be helpful for rational regimens in clinical treatment and promotion in novel drug discovery.

Efficacy and Prognostic Value of Partial Sensory Rhizotomy and Microvascular Decompression for Primary Trigeminal Neuralgia: A Comparative Study

Background

This study aimed to compare the efficacy and prognostic value of partial sensory rhizotomy (PSR) and microvascular decompression (MVD) for primary trigeminal neuralgia (PTN).

Material/Methods

From June 2010 to June 2012, 117 patients with PTN were recruited for the study, of which 52 cases were treated with MVD (the MVD group) and 65 cases were treated with PSR (the PSR group). Visual Analog Scoring (VAS) was performed at 1 and 2 weeks, and at 1, 3, and 6 month after surgery. The overall response rate (ORR) was determined 1 month after surgery. Barrow Neurological Institute score was adopted to value the reoccurrence at 6, 12, 24, and 36 months after surgery. A 3-year follow-up was conducted and the complications were recorded.

Results

The ORR 2 weeks after surgery in the MVD and PSR groups was 98.08% and 84.62%, respectively. One and 2 weeks after surgery, the VAS was lower in the MVD group than in the PSR group, but there was no significant difference in VAS between the 2 groups at 1, 3, and 6 months after surgery. Three years after surgery, the recurrence rate was significantly lower in the MVD group than in the PSR group. The recurrence-free survival time was longer in the MVD group than in the PSR group. The occurrence rates of herpes and total postoperative complications were significantly higher in the PSR group than in the MVD group.

Conclusions

Compared with PSR, MVD is more suitable for PTN treatment, with less disturbance, lower recurrence rate, and better efficacy.

The Study of Calcium, Phosphonium, Magnesium, and Ferrum Concentration in Serum of Patients With Primary Trigeminal Neuralgia

OBJECTIVE

To measure the concentration of 4 essential elements (Ca, P, Mg, Fe) in serum of patients with primary trigeminal neuralgia. And evaluate the role of the 4 elements in serum on the pathogenesis of trigeminal neuralgia (TN), and the relevance of etiology.

METHODS

From June 2013 to June 2014, a number of 80 patients with primary trigeminal neuralgia were collected. We present a retrospective review of the concentration of 4 essential elements with those of control group of 80 patients without TN. The concentrations of 4 elements were measured with Olympus AU 400 automatic biochemistry analyzer.

RESULTS

In primary TN patients, the concentration of Ca, P, Mg in serum is lower than the control group obviously (P <0.05), but the concentration of Fe in serum is higher than the control group obviously (P <0.05). Along with level of the VOS improved, the concentration of Ca, P, and Mg in serum becomes lower and lower. However, along with level of the VOS improved, the concentration of Fe in serum becomes higher and higher.

CONCLUSION

Patients with primary TN, the change of 4 elements concentration in serum is connected with biochemical material change. The change of the microelement may play an important role in the development of Trigeminal neuralgia, possibly demyelinating lesions.